Work

Origin of Long-Lived Coherences in Light-Harvesting Complexes

Year: 2012

Type: article

Abstract: A vibronic exciton model is applied to explain the long-lived oscillatory features in the two-dimensional (2D) electronic spectra of the Fenna-Matthews-Olson (FMO) complex. Using experimentally determined parameters and uncorrelated site energy fluctuations, the model predicts oscillations with dephasing times of 1.3 ps at 77 K, which is in a good agreement with the experimental results. These long-lived oscillations originate from the coherent superposition of vibronic exciton states with dominant contributions from vibrational excitations on the same pigment. The oscillations obtain a large amplitude due to excitonic intensity borrowing, which gives transitions with strong vibronic character a significant intensity despite the small Huang-Rhys factor. Purely electronic coherences are found to decay on a 200 fs time scale.

Source: The Journal of Physical Chemistry B

DOI: 10.1021/jp304649c

Authors: Niklas Christensson, Harald F. Kauffmann, Tõnu Pullerits, Tomáš Mančal

Institutions: University of Vienna, TU Wien, Lund University, Charles University

Language: English

Topic: Spectroscopy and Quantum Chemical Studies

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funders: Grantová Agentura České Republiky, Austrian Science Fund, Vetenskapsrådet, Energimyndigheten

Award: G8071420099